Second Summer AP1000 under construction

Safety-related concrete has been poured for the basemat of the second AP1000 unit at the VC Summer plant in South Carolina. It comes seven months after the same milestone for the first unit there.

First concrete is poured at VC Summer 3 (Image: Scana)

The basemat provides a foundation for the containment and auxiliary buildings that are within the unit's nuclear island. Measuring 1.8 metres thick, the basemat required some 7000 cubic metres of concrete to cover an area about 76 metres by 49 metres. The concrete-pouring process took just over 43 hours and was completed on 4 November.

The two new 1117 MWe Westinghouse AP1000s will share a site with an existing pressurised water reactor, VC Summer unit 1, operated by South Carolina Electric & Gas (SCE&G), a subsidiary of Scana Corporation, and co-owned by SCE&G and Santee Cooper.

SCE&G and Santee Cooper signed an engineering and procurement contract with a consortium of reactor vendor Westinghouse and the Shaw Group in May 2008, and by September 2011 site preparation work was advanced. Shaw was acquired by Chicago Bridge & Iron Company (CB&I) in July 2012.

Westinghouse's senior vice president for nuclear power plants Jeff Benjamin commented, "Thanks to the lessons we learned from the unit 2 concrete pour and also from our other construction projects, we were able to complete this milestone safely and even more efficiently." Concrete pouring for the basemat of unit 2 took just over 50 hours to complete.

About 2000 workers are currently involved in the construction of the two AP1000 units at Summer. The number of workers will peak at about 3000 over the next three to four years. Once operating, the two units will provide between 600 and 800 permanent jobs. Unit 2 is currently scheduled to be completed in late 2017 or early 2018, followed by unit 3.

Benjamin noted some of the progress that has been made in the construction of unit 2, including the placement of both the containment vessel bottom head and the reactor vessel support module, as well as concrete placement that will enable further progress on the nuclear island. In addition, "one of the cooling towers is nearing completion, two condensers are placed, and significant progress continues on major modules, the containment vessel and the auxiliary building."

He added, "We look forward to many more milestones in the coming months, as work progresses on the next generation of nuclear plants to bring safe, clean, reliable electricity to the citizens they serve."

Two AP1000 units are also planned for Southern Company's Vogtle site in Georgia. First concrete at Vogtle 3 came in mid-March, just days after the same milestone at Summer 2. The pouring of first concrete at Vogtle unit 4 is expected imminently.

Four AP1000 reactors are being built in China, at Sanmen and Haiyang for China National Nuclear Corporation and China Power Investment Corp respectively. Sanmen unit 1 is expected to be the first AP1000 to begin operating. The unit is expected to begin generating electricity next year. All four Chinese AP1000s are scheduled to be in operation by 2016.